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We present a model for the equilibrium of solid planetary cores embedded in a gaseous nebula. From this model we are able to extract an idealized roadmap of all hydrostatic states of the isothermal protoplanets. The complete classification of the isothermal protoplanetary equilibria should improve the understanding of the general problem of giant planet(More)
We present a companion of the ≤ 2 Myr young classical T Tauri star GQ Lup in the Lupus star forming region at 140±50 pc from imaging, astrometry, and spectroscopy. With direct K-band imaging using VLT/NACO, we detected an object 6 mag fainter than GQ Lup located 0.7 ′′ west of it. Compared to images obtained 2 to 5 years earlier with Subaru/CIAO and HST/PC,(More)
To estimate the occurrence of terrestrial exoplanets and maximize the chance of finding them, it is crucial to understand the formation of planetary systems in general and that of terrestrial planets in particular. We show that a reliable formation theory should not only explain the formation of the Solar System, with small terrestrial planets within a few(More)
Today, many extrasolar planets have been detected. Some of them exhibit properties quite different from the planets in our solar system and they have eluded attempts to explain their formation. One such case is HD 149026 b. It was discovered by Sato et al. (2005). A transit-determined orbital inclination results in a total mass of 114 M ⊕. The unusually(More)
Of the over 400 known exoplanets, there are about 70 planets that transit their central star, a situation that permits the derivation of their basic parameters and facilitates investigations of their atmospheres. Some short-period planets, including the first terrestrial exoplanet (CoRoT-7b), have been discovered using a space mission designed to find(More)
We describe a relatively simple time-dependent con-vection model that can be coupled to the equations of radiation hydrodynamics. We show that it behaves in a physically plausible way in protostellar collapse flows and is quantitatively correct for nonlinear RR-Lyrae pulsations and the Sun. Together with the equations of radiation hydrodynamics the model(More)
We present the first coherent dynamical study of the cloud fragmentation-phase, collapse and early stellar evolution of a solar mass star. We determine young star properties as the consequence of the parent cloud evolution. Mass, luminosity and effective temperature in the first million years of the proto-Sun result from gravitational fragmentation of a(More)